centipedes!

Hard to tell from the pictures whether they are millipedes or centipedes. Centipedes have somewhat flattened bodies. Millipedes are pretty round. Do I see in your pictures ONE pair of legs per segment? That's a centipede. Millipedes have two. You should look. Centipedes are carnivores. They eat insects. Millipedes are vegetarians. They might eat your plants, but they probably just eat decomposing vegetation. If millipedes aren't on your plants, they're not a problem. If the centipedes are on your plants, it's probably a good thing!

It looks to me like 2 legs per segment:

Here's a conversation from the veggie gardening forum:

Bugs in the Garden

Poke it with a small stick lightly, if it curls up into a round shape it is millipede

They curl up every time I poke them.

Should I leave them alone?

You could gently remove them and release outside....they're not adding much value to your compost ;)

Millipedes in your soil are munching on your soil and helping to decompose vegetative stuff in it. They're "detritivores". Worms with legs. No, don't leave them alone. To the extent they stay off your plants, cheer them on!

Yes, Millipedes are vegetarians. They eat dead plant material. Not live plants.